The present invention relates to antennas, and more particularly, to dual band antennas having elements positioned in different planes.
With current developments in communication technology, many electronic devices need antennas which can receive and transmit signals in two frequency ranges. FIG. 10 shows a conventional dual band antenna. The conventional antenna is a planar inverted-F antenna and includes a planar radiating element 600. The radiating element 600 is divided by a non-conductive slot 601-602-603 into a first radiating branch located within a second radiating branch. A grounding plate 606 is located beneath and is electrically connected to the two branches. The two radiating branches and the grounding plate 606 are on a same planar surface. However, this planar structure antenna occupies a relatively large space in an electrical device and must be mounted onto a planar surface. The antenna is not very adaptable to installation in spaces having an irregular shape.
The present invention is directed to an improved dual band antenna, bended to position its elements in different planes, thereby occupying a relatively small space in an electrical device and being mountable into installation spaces having irregular shapes.
A main object of the present invention is to provide a dual band antenna occupying a relatively small space in an electrical device.
Another object of the present invention is to provide an antenna which is capable of being mounted into an installation space having an irregular shape.
A dual band antenna in accordance with the present invention comprises a first radiating branch, a second radiating branch, a grounding plate, a connecting plate, and a feed cable. The first radiating branch is in a first plane and is provided for receiving/transmitting signals in a first frequency band. A feed point is located on the first radiating branch. The second radiating branch is in a second plane perpendicular to the first plane and is provided for receiving/transmitting signals in a second frequency band. The grounding plate is in a third plane parallel to and facing the first plane and is soldered to an electrical device for fixing and grounding the antenna. The feed cable comprises a core conductor and an outer shield conductor around the core conductor. The core conductor is electrically connected to the feed point for feeding signals into the antenna. The outer conductor is soldered to the grounding plate.
The dual band antenna is bended so that the first and second radiating branches and the grounding plate of the antenna are each in a different plane. The antenna, therefore, occupies a relatively small area on a PCB or other surface in an electrical device. The angles between the first and second planes and between the second and third planes can be varied to fit a contour and size of an installation space of the electrical device, providing greater flexibility for fitting into the space. Additionally, this bended structure of the dual band antenna can change radiation patterns of the antenna to fit differing requirements.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.